The present invention relates to improvements in packaged-article vending machines of the type in which articles yet to be vended are ranked in succession among the turns of a horizontally arranged helix which projects forwardly above a horizontal tray ranked behind a glass front. Upon making payment for and selecting an article to be vended, the customer momentarily pauses and watches, as a motor turns the helix sufficiently to advance the leading packaged article product sufficiently that the leading packaged article falls off the front edge of the tray and descends through a vending space to land in an output chute where it is accessible for retrieval by the customer.
A popular feature of currently available packaged-article product-vending machines of the type referred to above which are snack-vending machines, is having at least one snack-vending column. Typically, this is a comparatively wide column, e.g. 5.5 inches (14 cm) wide, and at least two of the manufacturers which currently sell such machines provide two cooperatingly operated counter-rotatable helices for vending the comparatively large snack packages from such wide columns.
Typically, the product-vending machines which have product impounding and advancing helices arranged in respective side by side columns over a set of vertically spaced horizontally arranged trays, are of modular construction, in the sense that, depending on the sizes of the products which are to be vended, more or fewer trays can be provided, arranged to have more or fewer columns, the narrower columns being served by one helix each, and (in the above-described popular machines), the wider columns each being served by two helices which are arranged to be correspondingly counter-rotated.
Although modularity is considered to be an attractive feature, the need for two motorized helices operating coordinatingly to vend the packages in one wide column is believed not to be an optimal solution, due to the expense and complexity of requiring twice as many motorized helices for vending the product. In other words having it cost more to vend less is not the best, if the extra investment in motorized helices can be avoided.
The trouble with attempting to vend wide packages from a wide column using a single motorized helix, is that a single helix cannot be of arbitrary diameter; as a practical matter, it must be of a standard diameter for interchangeability, and so that its axially rearwardly projecting driving spindle is disposed the correct distance above the supporting tray for the spindle to be plugged through a corresponding hole in an upstanding flange at the rear of the tray for driven engagement with a correspondingly mounted motor. Thus, a single narrow helix even if initially centered in a wide column, when rotated will "walk" towards one side wall of the wide column, in the direction that the helix is rotated, particularly toward the front end of the helix, leaving so much room between the helix and the opposite sidewall of the wide column, that packages of product can slip sideways out of the turns of the helix near the front end of helix, resulting in jamming and/or failure to vend products from the column.
Others have attempted to solve the problem of how to serve a wide column by a single motorized helix by providing the tray floor and/or the column sidewalls with specially shaped plastic or metal V-shaped grooves or ridges that restrain sideways movement of the motorized helix. Although these solve the problem, they do so at considerable expense and at some penalty to interchangability of vending machine modules.